KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, technicians position the the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) science rack for installation into the Multi-Purpose Logisitics Module Leonardo. Leonardo will fly on Space Shuttle Atlantis on mission STS-121. The MELFI will provide cooling and storage for scientific experiment samples and perishable materials in four insulated containers, known as dewars, with independently selectable temperatures of -80 degrees Celsius, -26 degrees Celsius, and +4 degrees Celsius. MELFI will also be used to transport samples to and from the Station. MELFI is provided as laboratory support equipment by the European Space Agency. STS-121 is the second Return to Flight mission to the International Space Station. The launch window extends from Sept. 9 through Sept. 24.